The appropriate growth medium configuration is a crucial agronomic practice for water utilization, especially in arid areas. This issue is of particular importance in calcareous soils, where crop plants suffer from limited water and nutrient availability. Therefore, the present investigation aimed to estimate the yield performance and irrigation water use efficiency of sesame grown in different sowing patterns under different irrigation levels. A-2 year field trial was carried out in two summer seasons (2022 and 2023) in a strip-plot with a randomized complete block design using three replications. Three sowing patterns (flat, ridges, and beds) were allocated vertically. Irrigation water levels (100, 75 and 55% of evapotranspiration, ETc1, ETc2 and ETc3, respectively were applied and distributed horizontally. ETc1 × beds followed by ETc2 × ridges or beds in both seasons were the efficient combinations for producing the highest increases in capsules number plant−1. ETc1 × beds or ETc2 × ridges recorded the shortest height of the first capsule in both seasons. The maximum seed yield was achieved with ETc2 × beds in both seasons (1262.3 and 1313.3 kg ha−1), respectively, and ETc2 × ridges in the first season (1222.9 kg ha−1). ETc3 × beds (for oil % and oil yield ha−1 in both seasons) and ETc2 × beds (for oil yield ha−1 in the first season) exhibited the highest increases. ETc3 × beds interaction gave the maximum increase in irrigation water use efficiency in both seasons. The phenotypic correlation and path-coefficient analysis illustrated that the direct effects of seed index and capsules number plant−1 on seed yield plant−1 showed highly positive values (4.89 and 2.84 in 2022) and (1.01 and 1.01 in 2023). By adopting the beds method for cultivating sesame in arid zones, the irrigation programs should be modified via applying the deficit irrigation strategy to save water (about 25%) while keeping productivity. The findings provide new insights into optimizing resource use through beds sowing and moderate irrigation, contributing to sustainable sesame production in water-limited environments. Further, in order to develop stress-tolerant sesame varieties, breeders should focus primarily in breeding programs on improving capsules number plant−1 and seed index traits due to their great direct contribution influence on seed yield, as indicated by path-coefficient analysis.

Background Enriching biochar with nitrogen and using it as a slow-release nitrogen fertilizer is a promising strategy to avoid excessive use of chemical nitrogen fertilizers. Therefore, this study investigated the effect of different types of nitrogen-enriched biochar on the soil’s chemical properties, nitrogen use efficiency (NUE), and growth of spinach in calcareous sandy soil. This pot experiment included 9 treatments: control (unamended soil, CK), willow branches biochar (WB), apple of Sodom biochar (ASB), marvel grass biochar (MB), halfa grass biochar (HB), nitrogen-enriched willow branches biochar (NEWB), nitrogen-enriched apple of Sodom (NEASB), nitrogen-enriched marvel grass biochar (NEMB), nitrogen-enriched halfa grass biochar (NEHB). Nitrogen-enriched biochar and biochar were added at a level of 5 g kg−1 soil. This experiment was conducted on the spinach plant. Results Soil available nitrate increased significantly with adding NEHB, NEMB, NEWB, and NEASB compared to the control treatment. Adding HB, NEHB, NEMB, NEWB, and NEASB to the soil significantly improved the fresh and dry shoot of the spinach plant compared to the control. Applying HB, NEHB, NEMB, NEWB, and NEASB treatments increased the fresh shoot of the spinach plant over the control by ~62%, 245%, 237%, 275%, and 196%, respectively. On the other hand, adding MB, WB, and ASB treatments decreased the fresh shoot of the spinach plant relative to the control by ~14%, 3%, and 14%, respectively. Applying different types of nitrogen-enriched biochar significantly improved the NUE of spinach plant compared to the original biochar treatments. Conclusions Our results suggest that nitrogen-enriched biochar can be a promising strategy in sustainable agriculture to increase soil nutrient availability, improve spinach growth, and enhance nitrogen use efficiency in spinach. Nitrogen-enriched biochar can serve as an effective and cost-efficient alternative to chemical nitrogen fertilizers.